Definition of "impervious"

Although the Celebrity was almost impervious to sarcasm, he was now beginning to exhibit visible signs of uneasiness, the consciousness dawning upon him that his eccentricity was not receiving the ovation it merited.

1897 December (indicated as 1898), Winston Churchill, chapter V, in The Celebrity: An Episode, New York, N.Y.: The Macmillan Company; London: Macmillan & Co., Ltd.

For the past decade there were two more or less universally acknowledged truths about digital advertising. First, the rapidly growing industry was largely impervious to the business cycle.

2022 September 18, “The $300bn Google-Meta advertising duopoly is under attack”, in The Economist‎